The present invention relates to machines used for picking up scraps along a railroad bed. More specifically, this invention relates to a machine using magnets to pick up metallic scraps along a railroad bed.
The use of magnetic wheels to pick up metallic scrap along railroad beds is well known in the art. When disassembling a rail for replacement, several small metallic articles including spikes, tie plates, and anchors are removed and layed upon the railroad bed. Since it is desirable to clear the roadbed of such metallic articles and re-use such articles, the prior art has heretofore used various magnetic wheel constructions for picking up these metallic articles.
The following U.S. patents are illustrative of various prior art magnetic wheel pick up machines:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 3,690,264 Plasser et al September 12, 1972 3,731,455 Theurer May 8, 1973 4,225,429 Holley September 30, 1980 ______________________________________
The Plasser et al patent discloses a track working apparatus for assembling and disassembling tie plates. Additionally, a rotating magnetic means is used to pick up tie plates which are then deposited on an inclined conveyor belt by a doctor blade. The inclined conveyor belt lifts the tie plates up to a receptacle where they are deposited.
The Theurer patent shows the use of a conveyor belt having a magnet or magnets located within the conveyor belt. The conveyor belt picks up loose metallic articles upon a railroad bed and moves them horizontally for deposit onto an inclined conveyor belt.
Applicant's previous U.S. Pat. No. 4,225,429 shows a magnetic pick up wheel arrangement wherein scrap metallic articles are picked up by a magnetic wheel having a conveyor belt turning around its outside. The metallic articles are deposited upon the conveyor belt which is inclined to extend above a separate conveyor belt which is used for storing the metallic articles. As is best shown in FIG. 5 of the patent, separate magnetic wheels and associated conveyors may be used inside and outside the two rails upon a railroad bed. When cleaning up metallic articles upon a railroad bed wherein one of the two rails has been removed, a crawler (see especially FIGS. 8 and 9) may be lowered to support the side of the pick up machine which cannot be supported by its rolling wheels because of the previous removal of the rail on that side.
The prior art further includes a device which has been marketed by the present applicant and is shown schematically in simplified form in FIG. 1. This prior art machine 10 includes a frame structure 12 and four wheels 14 for rolling along a railroad track. Since the FIG. 1 view is an end view, only one of the right front wheel 14RF on the right side is shown, whereas the wheels are deleted from the left side for ease of illustrating various other features of this device. Attached to the frame structure 12 are mounting arms 13C, 13R, and 13L. A magnetic wheel 22 is shown on the left side of the machine 12 and is pinned to points 28C and 28L in respective parts 13C and 13L. The magnetic wheel 22 is turned by a hydraulic motor 16 by way of reduction gearing 24. Motor 16 is powered by a hydraulic pressure source (not shown) disposed on the machine frame 12. The magnetic wheel 22 is supported by a support beam 26 which extends to the centrally located vertical beam 13C where it is pivotally connected at pivot point 28C. The magnetic wheel 22 is in line with a plane which would be defined by the left side track wheels 14, which wheels are deleted from the view of FIG. 1 in order to show the operation of magnetic wheel 22.
As shown in FIG. 1, the left side rail has been removed from the railroad bed and only the right rail 18R remains. Accordingly, the two left side wheels 14 (not shown) would drop down to the roadbed 19 except for the magnetic wheel 22 which supports the left side of the machine frame structure 12.
As the machine 10 rolls along a railroad rail 18R, the magnetic wheel 22 picks up metallic articles such as tie plate 17. The tie plate 17 will rotate with the magnetic wheel 22 until it reaches a stripper tray (not shown) which causes the tie plate 17 and other metallic articles to be separated from the magnetic wheel 22 and drop into a storage means such as the storage conveyor disclosed in applicant's patent 4,225,429.
If desired to pick up tie plates at the right side of machine 10, the pin at 28L is removed and a hydraulic cylinder 21C having a piston (not shown) with arm 21A is actuated to lift support arm 26 (arm 21A is pinned thereto), magnetic wheel 22, motor 16, and gearing 24 to a center position. The support arm 26 may be pushed over center and magnetic wheel 22 lowered on the right side with hydraulic cylinder 21C and arm 21A preventing wheel 22 from dropping too fast. The support arm 26 pivots about 28C in a vertical plane throughout this change-over. The support arm 26 is now pinned to point 28R in 13R for operation of magnetic wheel 22 on the right side. By removing the pin holding support arm 26 to point 28R (or 28L), the support arm 26 can be lifted by hydraulic arm 21A to allow travel along a track with right and left rails.
Although the prior art devices have been generally useful in providing pick up of metallic scrap articles disposed upon a railroad bed, there have been several problems associated with various of these designs.
Those prior art designs which require an inclined conveyor belt are somewhat complex. Specifically, such inclined conveyor belts must be adapted to function while still allowing the magnetic wheel to rise and fall with the peaks and troughs in the railroad bed.
The prior art design shown in FIG. 1 is somewhat disadvantageous in that the magnetic wheel 22 is used to support the frame structure 12. Since this magnetic wheel must rise and fall with the peaks and troughs in the railbed, the machine 10 will likewise rise and fall with irregularities in the railbed. This places great stress on the machine and causes rapid wearing of the parts as the machine is used.
Another disadvantage common to several scrap pick up machines is their general inability to pick up one kind of metallic scrap or article, while not picking up other kinds. That is, most prior art magnetic wheel pick up machines pick up spikes and tie plates for example at the same time. Since spikes and tie plates eventually must be separated, picking up these articles together will require a separate sorting step.